CCTV新台址主楼抗震性能研究

中央电视台新台址主楼建筑造型和结构体系独特,结构动力特性和地震响应异常复杂。本文首先研究了结构的自振特性,研究结果表明,其1、2阶振型表现为沿两塔楼对角线方向的平动变形,并伴随塔身扭转变形以及大悬臂竖向振动,其3、5、7阶振型以扭转为主。在自振特性分析的基础上,应用有限元数值方法对结构的小震、中震弹性响应进行了分析。通过对构件承载性能的分析建立了弹塑性计算模型,并应用此模型进行了结构大震弹塑性时程响应和静力弹塑性推覆分析,依据抗震性能指标校核了结构及构件的承载力。基于FNA进行的大震弹塑性时程分析表明,最大层间位移角满足1/50的限值条件。推覆分析分别采用以加速度相关和质量相关的横向力分布模式,正、反向加载进行计算,按照目标位移法和能力谱法确定结构的地震响应以及推覆过程中塑性铰的分布状态。基于三套地震作用参数(《建筑抗震设计规范》(GB50011-2001),100年使用年限换算设防烈度及地震安评报告)的计算结果,综合评估了结构的

Analysis on earthquake response and aseismic load-carrying capability of New CCTV Building

The peculiar building style and special structural system of the New CCTV Building induce complicated dynamic attributes and intricate earthquake response to the structure.The primary purpose of this paper is to present the response of the New CCTV Building due to earthquake and to check out its aseismic load-carrying capability.The free vibration attribute was studied at first,and it was found that the first and secondary vibration mode were horizontal movements of the global structure in the direction of 45° or 135°,associated with the significant rotation of the towers and the vertical movement of the cantilevered structure.Then the elastic finite element method was employed to study the structure response stimulated by frequent and moderate earthquake.Through the investigation of load-carrying performance of main frame members,the elasto-plastic model of the structure was established.And with this model,time-history analysis in rare earthquake and push-over analysis was conducted.Apart from that,the status of all frame elements in chief structure system was checked out according to the aseismic performance index.The studies in this paper not only revealed the distinct dynamic attribute and aseismic load-carrying capability of the building,but also demonstrated the earthquake response of the building in earthquake of different intensities.All elastic and elastic-plastic analytical results come to a conclusion that the New CCTV Building meets the aseismic design requirement of Chinese code and the aseismic performance index specified in the study.The information and conclusion derived in this study is useful and significant in validating and improving the aseismic design of the New CCTV Building.